Shell Scripting Interview Questions and Answers You Need to Know

Shell scripting is a computer program or text file that provides the operating system with commands. The shell is the interface you use to command and execute those commands after receiving user input. Learning how to use different types of shells effectively can open the door to various job opportunities in India, including in public and private companies. 

When you interview for a position that involves shell scripting, preparing for the technical questions pertaining to your knowledge of shells and how to write different shell scripts is essential. Though exact questions will vary, understanding the following questions will help you be more prepared and self-assured in your meeting. 

1. What is a shell?

Why the interviewer is asking this: The interviewer wants to assess your basic knowledge of shells.

A shell is a program or interface that accepts and translates user commands so the operating system can perform those commands or go between the user and the kernel. The program is a command-line interpreter that converts user input into something the kernel can understand.

2. Tell me about different types of shells.

Why the interviewer is asking this: The interviewer wants to see which types of shells you have worked with and understand.

When the interviewer asks you about the different types of shells, it’s a good opportunity to show the depth of your knowledge. When you name shells, such as the core types of shells: C shell, Bourne shell, Bourne Again shell (BASH), and Korn shell, make sure you add a sentence or two about each. For instance, C shell creates a shortcut for the home directory, while BASH creates a default for the current date and time.

You could take this opportunity to mention if you have a favourite type and explain why. Doing so demonstrates your excitement about the job you are interviewing for.

3. What is a shell variable? 

Why the interviewer is asking this: The interviewer is assessing the depth of your knowledge of shell variables and how to use them. 

Shell script variables, often stored as string variables, form the core of a shell script. These variables define the program structure and function and determine how to manipulate information within the program. Shell variables last through execution.

4. Why are shell scripts important?

Why the interviewer is asking this: The interviewer wants to know how you use shell scripts and how you believe they improve the workflow.

Shell scripts improve workflow for programmers by avoiding repetitive tasks and improving efficiency. Shell scripts also help with debugging, functionality, routine backups, and system monitoring.

5. In UNIX shell scripting, why does the remote server need to connect to the system? 

Why the interviewer is asking this: The interviewer wants to know if you can execute special commands remotely.

Managing servers remotely is important for users to access systems from any location. This is done by remotely executing scripts on the local machine. Remember to include an authentication process with usernames and passwords for security concerns.

6. How is an open client driver used in shell scripting?

Why the interviewer is asking this: The interviewer wants to know if you understand how to connect to a database server.

You use open client drivers to connect to a database server through the isql utility. Data can’t always be kept in one location; thus, connecting to a database server is useful so all users can be accommodated. 

7. What are the advantages of shell scripting?

Why the interviewer is asking this: The interviewer wants to understand why you chose this profession.

This question is purposely open-ended so that you can give your thoughts. Shell scripting is a way you can develop your operating system with the features that are most relevant to you. You can design software according to your unique platform. Having at least two to three favourite reasons for using shell scripting ready can showcase your excitement about the position. 

8. What are the negatives of shell scripting?

Why the interviewer is asking this: The interviewer wants to find out whether you know the limitations of shell scripting. 

This is a great time to show that you understand the drawbacks of shell scripting and explain how you can avoid errors and protect sensitive data. For example, poorly designed shells can cause costly errors. The initial design is slow, and it takes time for the platform to get to a higher speed. Even a simple typo during the creation can delete data, including partition data. It doesn’t necessarily work well with other operating systems. 

9. What are soft and hard links?

Why the interviewer is asking this: The interviewer wants to know whether you can effectively use coding shortcuts.

“Links” are shortcuts created on Linux. The interviewer is asking about soft and hard links to file names, so they know you can use them to secure the links on different file systems. Hard links, however, link to the inode of files and are kept in your file system.

10. What are the three file permission types in shell scripting?

Why the interviewer is asking this: The interviewer wants to know if you can design multi-user programs effectively.

The interviewer is asking about the three permission types because you must choose among them as you do shell scripting. The three different types of permissions are read, write, and execute. Which one you choose depends on who you want to be able to have access to the shell. For instance, read permissions have the strictest limits to the file system. Write permissions allow users to edit the file, and execute permissions allow users to run the program.

11. What are the descriptions and commands within the Linux directory?

Why the interviewer is asking this: The interviewer wants to know how you use different commands and understand your experience with different types of programs.

This question is a great time to share your knowledge of different commands and their purposes. For example, the built-in command “pwd” means “print working directory”. The command displays the user directory, where the working location is, the directory of the user, and the working path. You can share examples of how you have used commands in past projects and discuss which commands you will use for the position you are interviewing for. 

12. What are graphical shells?

Why the interviewer is asking this: The interviewer wants to see if you understand different shell types and their uses.

Graphical shells use the graphical user interface to interact with programs and simplify functions for switching, opening, moving, closing, and resizing windows. You may also discuss how they compare with command-line shells, which users often employ for automation.

13. Why do you put a dot before a file name? 

Why the interviewer is asking this: The interviewer wants to know whether you know security functions within shell scripting.

Adding a dot before a file name hides a file from lists when appropriate. You won’t see the file displayed in the list of files in the shell, but you will see the file in the directory, which you can access with the command “-a”, “-d”, or “echo”.

14. What’s the function of the continue command?

Why the interviewer is asking this: The interviewer is assessing which commands you have used and whether you have the skills to perform the job tasks they need.

Linux programmers frequently use the continue command to stop iterations without exiting the whole loop. You’re skipping a loop and taking a break rather than creating an ending.

Get started with Coursera

Before an interview, brushing up your skills in Linux and UNIX may help you feel confident with your shell scripting skills. Consider taking highly rated courses on Coursera, such as Hands-on Introduction to Linux Commands and Shell Scripting or Linux Fundamentals. Considering a career in IT support? Build the skills you need with the Google IT Support Professional Certificate.